I looked for a long time for a good helm seat. My vessel has only an upper helm so the movement side to side from a big broadside from a big sport-fisher can be a concern. Numerous times I've been toppled from my four-legger helm chair, so whatever under-structure there was for a permanent mount would need to be substantial enough to bear my 240 lbs. on the end of a 36" lever (pedestal), plus the weight of the chair. Instead of trying to build my own chair, I looked for the heaviest structure I could find and decided on a Stidd 500.
Ft. Lauderdale area is an excellent choice to find high-quality take-outs among the frequent super-yacht refits. The wives might not like the color or the style of this or that, so if whatever it is happens to be easily removed, it is cast to the side and replaced with new instead of any effort to paint, re-plate or re-cover. When I first saw the chair I wanted, it was one of two vanilla leather Stidd 500 helm chairs taken from the same boat. Both were marked $2495, the first one of which was sold in days. The second one languished and after six months on the floor, looked like hell. I offered the salvage 900 bucks and prayed there was nothing seriously wrong with it. It took a lot of cleaning to bring it back to new looking, but there wasn't even a blemish. Later, I found an equally horrible looking SS foot rest for $60 which cleaned up perfectly, and a terribly abused maroon Stidd pedestal that needed a few parts to complete, but only cost me $90. I had to take the pedestal to a machine shop to shorten it correctly to preserve its adjustments ($325), and then I sanded and faired the powder coat as good as I could, finally finishing it in matching vanilla color enamel. All together, the effort took two years, a bit of patience and maybe $1500 for a near perfect example. Stidd, by the way, sent me the parts I needed to complete the pedestal at no charge.
A good, high quality, heavily constructed chair is possible if you're not in a hurry.